With greater attention being given to lawn care the increased use of a rotary mower, either the push type or riding mowers has been impressive over the last twenty-five or thirty years in North America.
Existing rotary blades are composed of a flat piece of steel whose opposite ends are slightly turned and whose leading edge near each end is a bevel to the blade which acts as a cutting element to the grass. The blade rotates by being removably attached as by bolts to the rotary shaft of a two or four cycle engine. When the grass is long, a great amount of grass is ejected from the side-shoot, clutters the ground with grass clippings making the cut grass unesthetically looking. It generally is raked or bagged in order to improve appearance.
Recently mulching mowers have been invented which have single curves or double curves in parallel with deflectors or kickers and some mulching mowers have closed decks so as to attempt to hold the grass in suspension while the blade rotates so as to cut the grass into fine particles and hence mulch it.